ABSTRACT Vietnam has a smoking prevalence that is the second highest among South East Asian countries (SEACs). With a population of approximately 90 million, Vietnam also has the second largest total number of adult smokers (over 16 million) in SEA. According to the World Health Organization (WHO), most reductions in mortality from tobacco use in the near future will be achieved through helping current users quit. Tobacco use treatment, as defined by the U.S. Preventive Health Service Guideline (Guideline) on Treating Tobacco use and Dependence, is evidence-based and highly cost-effective. Yet, in the U.S. and globally, adoption of recommended care is suboptimal. The objective of this proposal is to fill the current research-to-practice gap by conducting a randomized controlled trial that compares the effectiveness and cost effectiveness of two practical and highly replicable strategies for implementing evidence-based guidelines for the treatment of tobacco use in public health clinics in Vietnam. The proposed implementation strategies draw on evidence- based approaches, and the WHO's recently released guidelines for implementing Article 14 of the Framework Convention on Tobacco Control (FCTC). The FCTC is an evidence-based treaty that was developed by the WHO in response to the globalization of the tobacco epidemic. Vietnam ratified the FCTC in 2004; however, they have not taken steps to implement Article 14 which specifies the need to integrate best practices for treating tobacco use and dependence into routine preventive care. The proposed implementation strategies also build on the growing literature that supports the effectiveness of integrating community health workers as members of the health care team to improve access to preventive services. We propose a two arm, cluster randomized controlled trial that will compare the effectiveness and cost effectiveness of two multi component strategies for implementing tobacco use treatment guidelines: 1) Technical assistance, training, plus clinical reminder system (TTC) vs. 2) TTC + referral to a community health worker (CHW). The primary outcome is provider adherence to tobacco use treatment guidelines (implementation effectiveness). The secondary outcome is six month biochemically verified smoking abstinence. We will conduct a formative evaluation prior to implementation to evaluation to assess current policies, systems of care and practice-level barriers and facilitators for tobacco use screening and treatment in public health clinics and inform modifications to the implementation strategies. Guided by an organizational model of innovation implementation, we will also examine organizational factors associated with effective implementation of provider adherence to tobacco use treatment guidelines. The study will be conducted in 26 public health clinics in two districts (rural and urban). The long-term goal of this research is to provide critical new knowledge to facilitate the widespread implementation, dissemination and sustained utilization of evidence-based tobacco use treatment strategies globally and in the U.S.